A method for utilizing molasses to compound ferrous ions to synergistically strengthen an anaerobic ammonia oxidation denitrification system

Abstract

The application discloses a method for utilizing molasses to compound ferrous ions to synergistically strengthen an anaerobic ammonia oxidation denitrification system, and belongs to the technical field of wastewater biological treatment. In the anaerobic condition, pretreated molasses and ferrous ions (Fe 2+ ) are added to wastewater containing ammonia nitrogen and nitrite nitrogen to construct a synergistically strengthened denitrification system. The pretreated molasses serves as an exogenous electron shuttle to accelerate extracellular electron transfer of anaerobic ammonia oxidation bacteria (AnAOB), and forms a synergistic effect with Fe 2+ , so that the relative activity of AnAOB is increased by 3-12.6 times compared with that of a blank group. The application solves the technical bottleneck of limited activity increase and poor running stability of AnAOB in the prior art, reduces the running cost by using an industrial by-product, and is suitable for industrialized treatment of high-concentration ammonia nitrogen wastewater.

Description

Technical Field

[0001] This invention belongs to the field of wastewater biological treatment technology, specifically relating to a method that utilizes industrial byproduct waste molasses as an electron shuttle to composite ferrous ions (Fe... 2+ A method for synergistically enhancing the denitrification efficiency and stability of the Anammox system. Background Technology

[0002] With the continuous advancement of global industrialization and urbanization, the discharge of industrial wastewater and municipal sewage containing high concentrations of ammonia nitrogen is increasing daily, posing a severe threat to aquatic ecosystems. While traditional biological nitrification-denitrification processes dominate wastewater treatment, they suffer from drawbacks such as high aeration energy consumption, large external carbon source requirements, and high greenhouse gas (e.g., N2O) emissions. Under increasingly stringent total nitrogen (TN) emission standards, developing low-carbon, energy-saving, and efficient biological nitrogen removal technologies has become an important research direction in the water treatment field.

[0003] Anaerobic ammonia oxidation (AAO), a biological process driven by anaerobic ammonia-oxidizing bacteria (AnAOB), directly converts ammonia nitrogen into nitrogen gas using nitrite as an electron acceptor under anoxic conditions. As a key wastewater denitrification technology, it requires no external organic carbon source, and due to its autotrophic growth characteristics, it produces extremely low sludge, significantly reducing operating costs. However, the extremely long doubling time of AnAOB and its high sensitivity to environmental fluctuations lead to technical bottlenecks in Anammox reactors, including long start-up cycles, poor stability, and difficulties in maintaining activity, severely limiting their large-scale engineering application.

[0004] Currently, most enhancement methods for the Anammox system involve the addition of a single component, which has certain technical limitations: the addition of ferrous ions alone can only increase the activity of key intracellular enzymes in AnAOB to a limited extent, but cannot effectively accelerate extracellular electron transfer, resulting in a limited increase in bacterial activity. Furthermore, long-term operation is prone to Fe... 2+ The problems include oxidative deactivation and insufficient system stability. While pure chemical electron shuttles can accelerate electron transfer, they are costly and difficult to scale up for engineering applications. In addition, existing research focuses on short-term enhancement of AnAOB activity, neglecting the engineering challenge of long-term system stability, and has not adopted a synergistic enhancement method between waste molasses and ferrous ions. Summary of the Invention

[0005] To address the technical challenges of poor operational stability, weak shock resistance, and limited engineering applications in existing anaerobic ammonia oxidation technologies, this invention provides a method for synergistically enhancing an anaerobic ammonia oxidation denitrification system using waste molasses composite ferrous ions.

[0006] The objective of this invention is achieved through the following technical solution: A method for synergistically enhancing an anaerobic ammonia oxidation denitrification system using waste molasses and ferrous ions, the method specifically comprising: Under anaerobic conditions, ferrous ions and electron shuttle waste molasses are added to the wastewater containing anaerobic ammonia oxidation activated sludge to carry out an anaerobic ammonia oxidation reaction. During the reaction, the anaerobic environment is maintained, and the dissolved oxygen (DO) is controlled between 0.2 and 0.5 mg / L, and the system pH is controlled between 7.0 and 7.8 to suit the growth of anaerobic ammonia oxidizing bacteria. The wastewater to be treated contains ammonia nitrogen and nitrite nitrogen.

[0007] Furthermore, the method employs either a sequential batch processing (SBR) or a continuous stream operation mode. Furthermore, in the method, the initial volatile suspended solids concentration (MLVSS) of the sludge mixture is controlled to be 2000–3000 mg / L; Furthermore, in the method, the reaction temperature is controlled at 35±1℃.

[0008] Furthermore, in the method, the final concentration of ferrous ions in the system is controlled to be 1–10 mg / L (preferably 5 mg / L). Furthermore, the ferrous ions are added in the form of ferrous sulfate heptahydrate; Furthermore, the waste molasses is used after pretreatment. The pretreatment steps are as follows: dilute the waste molasses with warm water at 50-60℃ at a mass ratio of 1:50 to 1:100, stir evenly, and adjust the pH to 4.0-5.0 using inorganic acids such as hydrochloric acid and sulfuric acid to promote the precipitation of macromolecular impurities; allow the diluted solution to settle naturally for 12-24 hours to remove insoluble suspended matter and collect the clarified solution; sterilize the clarified solution with high-pressure steam, cool it, and store it at 4℃ in the dark.

[0009] Furthermore, in the method, the volume concentration of the pretreated waste molasses in the control system is 1% to 5% (preferably 2%).

[0010] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. Pretreated waste molasses contains redox active components such as humic substances and quinone groups. These components act as electron shuttles, increasing the extracellular electron transfer rate and allowing more electrons to enter the cell and participate in enzymatic reactions with Fe as the active center. Experimental data show that the relative activity (RAA) of AnAOB in the combined addition group (FF2 group) increased by up to 12.6 times, which is higher than the arithmetic sum of the effects of adding waste molasses and ferrous ions alone, demonstrating a strong synergistic enhancement effect.

[0011] 2. During the 64-day operating cycle, a single Fe 2+The addition of ferrous ions often faces problems such as easy oxidation and deactivation or insufficient system stability. However, this invention constructs a highly resilient denitrification system through the synergistic combination of electron shuttles and functional ions. Under optimal process conditions, the total nitrogen removal rate of the composite enhancement group can be consistently maintained at a high level of 80% to 95%. Its operational stability and resistance to shock loads are superior to those of the single-component operation mode, effectively solving the technical problems of easy instability and difficulty in maintaining activity in anaerobic ammonia oxidation systems in practical engineering applications.

[0012] 3. This invention uses molasses, a byproduct of the sugar industry, as an electron shuttle to replace chemical reagents, resulting in significant cost advantages. The method is simple to operate and easily applicable to existing anaerobic ammonia oxidation reactors, providing new technical support for the treatment of high-concentration ammonia nitrogen wastewater. Attached Figure Description

[0013] Figure 1 This is a graph showing the total nitrogen removal effect of ferrous sulfate at different concentrations in Example 1; Figure 2 This is a graph showing the relative activity of anaerobic ammonia-oxidizing bacteria at different concentrations of ferrous sulfate in Example 1; Figure 3 Fe in Example 2 2+ Activity graph of anaerobic ammonia oxidizing bacteria in combination with 1% waste molasses; Figure 4 Fe in Example 3 2+ Activity graph of anaerobic ammonia oxidizing bacteria in combination with 2% waste molasses; Figure 5 Fe in Example 4 2+ Activity graph of anaerobic ammonia oxidizing bacteria in combination with 3% waste molasses; Figure 6 Fe in Example 5 2+ Activity graph of anaerobic ammonia oxidizing bacteria in combination with 4% waste molasses; Figure 7 Fe in Example 6 2+ Activity diagram of anaerobic ammonia oxidizing bacteria relative to 5% waste molasses; Figure 8 Fe in Example 3 2+ The graph shows the change in total nitrogen removal rate when combined with 2% waste molasses. Detailed Implementation

[0014] The technical solution of the present invention will be described in detail below with reference to the embodiments and accompanying drawings. The following embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0015] The anammox activated sludge used in the following examples was mature anammox activated sludge purchased from Angel Yeast. The sludge was in the following acclimation state: mature and stable, with stable denitrification performance and no bacterial bulking. The anammox sludge was washed three times before the reaction to remove impurities.

[0016] The industrial waste molasses used was obtained from Qinfeng Sugar Industry Co., Ltd. in Qinzhou, Guangxi. The main components of the waste molasses include 45-50% total sugar, of which 15-20% of the total sugar is reducing sugar.

[0017] Waste molasses is pretreated before use: Industrial waste molasses is diluted with warm water at 55℃ at a mass ratio of 1:100, stirred evenly, and then the pH is adjusted to 4.5 with 10wt% hydrochloric acid to promote the precipitation of macromolecular impurities; the diluted solution is centrifuged in an 8000 rpm centrifuge for 10 min to remove insoluble suspended matter and the clear liquid is collected; the clear liquid is sterilized by high-pressure steam at 121℃ for 20 min, and after cooling, the pretreated waste molasses is obtained and stored at 4℃ in the dark for later use.

[0018] Example 1

[0019] This embodiment is used to determine the optimal concentration of ferrous sulfate added alone, providing basic data for subsequent synergistic experiments. The specific method is as follows: Simulated wastewater: Using tap water as a base, NH4Cl and NaNO2 are added to make the initial NH4Cl... + -N and NO2 - -N concentrations were 100 mg / L and 132 mg / L, respectively. NaHCO3 (750 mg / L), MgSO4·7H2O (300 mg / L), CaCl2·2H2O (230 mg / L), and KH2PO4 (10 mg / L) were added simultaneously. In addition, 1 mL of trace element aqueous solution was added per liter of wastewater to simulate real wastewater (trace element aqueous solution formula: NiCl2·6H2O 0.19g, MnCl2·4H2O 0.99g, CuSO4·5H2O 0.25g, CoCl2·6H2O 0.24g, EDTA·2Na 15g, H3BO3 0.43g, Na2MoO4·2H2O 0.16g, Na2SeO3 0.1g, Na2WO4 0.05g, diluted to 1 L with water).

[0020] The initial pH was adjusted to 7.5 ± 0.1 using 1 mol / L HCl or 1 mol / L NaOH to match the suitable growth range of anaerobic ammonia-oxidizing bacteria. The prepared wastewater maintained a stable pH of 7.5–7.8 during the test period thanks to its own NaHCO3 / CO2 buffer system.

[0021] A 250 mL anaerobic serum bottle was used as the anaerobic ammonia oxidation reactor (effective volume 200 mL). Simulated wastewater was added first when starting the reactor, and high-purity nitrogen was introduced for 20 min to maintain the anaerobic environment. The dissolved oxygen (DO) was controlled between 0.2 and 0.5 mg / L. Anaerobic ammonia oxidation activated sludge was inoculated into the serum bottle, and the inoculation volume accounted for 10-15% of the total effective volume of the reaction system. In this example, the initial volatile suspended solids concentration (MLVSS) of the sludge mixture after inoculation was 2555 mg / L.

[0022] The sealed reactor was placed in a constant temperature incubator, with the oscillation speed set at 150 rpm, and the reaction temperature controlled at 35±1℃ throughout the process. The reactor adopted a sequencing batch reactor (SBR) operation mode with a hydraulic retention time (HRT) of 24 h. Starting from the second day, the reactor was allowed to settle for 30 min each day, and 75% of the supernatant (150 mL) was slowly discharged using a syringe, retaining 50 mL of the mixed liquid containing sludge. Then, an equal amount of fresh simulated wastewater was added, along with a certain amount of ferrous sulfate heptahydrate. High-purity nitrogen gas was then introduced into the reactor for 20 min, initiating the anaerobic denitrification reaction stage of the next cycle.

[0023] The supernatant was pretreated by filtration through a 0.45 μm aqueous filter membrane, and then ammonia nitrogen (NH4) was determined by Nessler's reagent spectrophotometry, N-(1-naphthyl)-ethylenediamine spectrophotometry, and alkaline potassium persulfate digestion ultraviolet spectrophotometry, respectively. + -N, Nitrite nitrogen NO2 - Calculate the total nitrogen removal rate based on the N-N and total nitrogen concentrations; The entire experiment was run continuously for 64 days. After the operation period ended, the mud-water mixture was taken to test the specific activity (SAA) of anaerobic ammonia oxidizing bacteria and the relative activity (relative AnAOB activity, RAA) was calculated.

[0024] Six parallel experiments were set up, and the Fe content in the system was controlled. 2+ The final concentrations added were 0 (blank control group CK), 1, 3, 5, 7, and 10 mg / L. Three replicates were set up for each experiment.

[0025] Total nitrogen removal rate calculation: TN removal rate (%) = (TN in -TN out ) / TN in ×100%; Where: TN in The total nitrogen concentration (TN) in the influent on that day is expressed in mg / L. out The total nitrogen concentration in the effluent on that day is expressed in mg / L.

[0026] Relative AnAOB activity (%) = Experimental group SAA / Blank control group SAA × 100%; , g N / (g VSS·d); NH4 + -N consumption rate, mass of ammonia nitrogen consumed per unit volume of mixed solution per hour, mg N / (L·h); NO2 - -N consumption rate, mass of nitrite nitrogen consumed per unit volume of mixed solution per hour, mg N / (L·h); MLVSS: concentration of volatile suspended solids in the mixed solution, g / L.

[0027] Changes in total nitrogen removal rate and relative anammox activity of anammox are as follows: Figure 1 and Figure 2 As shown, an appropriate amount of Fe 2+ Adding Fe can significantly improve the denitrification efficiency of the system, mainly because Fe 2+ As a key component of the active center for core enzymatic reactions in AnAOB cells (such as hydrazine synthase HZS and hydrazine dehydrogenase HZO), it can effectively activate metabolic pathways within the bacteria. However, when the concentration is too high, Fe... 2+ It exhibited certain cytotoxicity against AnAOB, thereby inhibiting bacterial cell activity. 5 mg / L Fe 2+ The optimal dosage was found to enhance both AnAOB activity and total nitrogen removal rate, making it the preferred dosage for subsequent synergistic experiments.

[0028] Example 2

[0029] This example is used to verify the relationship between low concentration (1%) waste molasses and Fe. 2+ The synergistic enhancement effect was achieved by referring to Example 1, except that the parallel experiments of ferrous sulfate heptahydrate were replaced with: Blank control group (CK): No waste molasses and Fe were added. 2+ ; Separate waste molasses group (F1): Add 1% of pretreated waste molasses according to the total volume of the final reaction system; Fe alone 2+ Group (Fe5): Fe was added to a final concentration of 5 mg / L. 2+ ; Composite group (FF1): Simultaneously adding 1% of the total volume of pretreated waste molasses and 5 mg / L Fe to the final reaction system. 2+ ; Supernatant was collected every 24 hours, and the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the supernatant were tested. The total nitrogen removal rate was calculated. After the 64-day operation cycle, the sludge-water mixture was collected to test the specific activity (SAA) of anaerobic ammonia oxidizing bacteria and to calculate the relative activity (RAA) of anaerobic ammonia oxidizing bacteria.

[0030] like Figure 3As shown, the relative anaerobic ammonia oxidizing activity (RAA) of the FF1 complex group was higher than that of the F1 and Fe5 groups. The pretreated waste molasses, rich in humic substances and quinone groups, and other redox-active components, acted as exogenous electron shuttles in the system, constructing a highly efficient extracellular electron transport channel. This accelerated the transfer rate of electrons from small organic molecules or metabolic donors to the surface of AnAOB cells, allowing more electrons to rapidly enter the cell and participate in enzymatic reactions with iron as the active center. This overcame the technical bottleneck of slow extracellular electron transport in AnAOB under conventional conditions.

[0031] Example 3

[0032] This embodiment is used to verify the optimal concentration (2%) of waste molasses and Fe. 2+ The synergistic enhancement effect was achieved by referring to Example 1, except that the parallel experiments of ferrous sulfate heptahydrate were replaced with the following experiments: Blank control group (CK): No waste molasses and Fe were added. 2+ ; Separate waste molasses group (F2): Add pretreated waste molasses accounting for 2% of the total volume of the final reaction system; Fe alone 2+ Group (Fe5): Fe was added to a final concentration of 5 mg / L. 2+ ; Composite group (FF2): Simultaneously adding 2% of the total volume of pretreated waste molasses and 5 mg / L Fe to the final reaction system. 2+ ; Supernatant was collected every 24 hours to test the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen. The total nitrogen removal rate was calculated. After the 64-day operation cycle, the sludge-water mixture was collected to test the specific activity (SAA) of anaerobic ammonia oxidizing bacteria and to calculate the relative activity (RAA) of anaerobic ammonia oxidizing bacteria.

[0033] like Figure 4 The results showed that, compared to the blank control group, the activity of F2 group alone increased by 2.2 times, the Fe5 group by 3.4 times, and the relative activity (RAA) of AnAOB in the FF2 composite group increased by as much as 12.6 times, far exceeding the sum of the two alone, demonstrating a strong synergistic effect of electron shuttle. When the volume fraction of waste molasses was 2%, the concentration of electron shuttle and Fe 2+ The activation sites reached their optimal state. At this time, the increased extracellular electron transport rate driven by molasses and the intracellular metabolic enzyme activity driven by iron induced AnAOB to enter an optimal growth and metabolic state, resulting in a stable total nitrogen removal rate of 80%–95% in the FF2 group during the 64-day operation period. Figure 8 This system has the strongest impact resistance and is the best solution.

[0034] Example 4

[0035] This example is used to verify the relationship between medium-concentration (3%) waste molasses and Fe. 2+ The synergistic enhancement effect was achieved by referring to Example 1, except that the parallel experiments of ferrous sulfate heptahydrate were replaced with the following experiments: Blank control group (CK): No waste molasses and Fe were added. 2+ ; Separate waste molasses group (F3): Add pretreated waste molasses accounting for 3% of the total volume of the final reaction system; Fe alone 2+ Group (Fe5): Fe was added to a final concentration of 5 mg / L. 2+ ; Composite group (FF3): Simultaneously adding 3% of the total volume of pretreated waste molasses and 5 mg / L Fe to the final reaction system. 2+ ; Supernatant was collected every 24 hours, and the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the supernatant were tested. The total nitrogen removal rate was calculated. After the 64-day operation cycle, the sludge-water mixture was collected to test the specific activity (SAA) of anaerobic ammonia oxidizing bacteria and to calculate the relative activity (RAA) of anaerobic ammonia oxidizing bacteria.

[0036] like Figure 5 As shown, although RAA activity was significantly higher than the blank control group, the activity growth curve tended to flatten compared to the 2% dosage. This was mainly because with further increases in molasses concentration (3%), the residual trace amounts of reducing sugars and other biodegradable organic matter increased accordingly. Although the electron shuttle effect brought about by humic substances was still at play, the excess organic load began to trigger the synergistic metabolism of potential heterotrophic denitrifying bacteria in the system. Heterotrophic bacteria and autotrophic AnAOB generated slight competitive pressure on the limited substrate (such as nitrite) and living space, resulting in a slowdown in the growth slope of AnAOB activity.

[0037] Example 5

[0038] This example is used to verify the relationship between high concentration (4%) waste molasses and Fe. 2+ The synergistic enhancement effect was achieved by referring to Example 1, except that the parallel experiments of ferrous sulfate heptahydrate were replaced with the following experiments: Blank control group (CK): No waste molasses and Fe were added. 2+ ; Separate waste molasses group (F4): Add pretreated waste molasses accounting for 4% of the total volume of the final reaction system; Fe alone 2+ Group (Fe5): Fe was added to a final concentration of 5 mg / L. 2+ ; Composite group (FF4): Simultaneously adding 4% of the total volume of pretreated waste molasses and 5 mg / L Fe to the final reaction system. 2+ ; Supernatant was collected every 24 hours, and the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the supernatant were tested. The total nitrogen removal rate was calculated. After the 64-day operation cycle, the sludge-water mixture was collected to test the specific activity (SAA) of anaerobic ammonia oxidizing bacteria and to calculate the relative activity (RAA) of anaerobic ammonia oxidizing bacteria.

[0039] like Figure 6 As shown, during the 64-day operation period, although the RAA activity in group FF4 was still better than that of the single-component addition, the increase was lower than that in groups with 2% and 3%. As the molasses concentration increased to 4%, the chemical oxygen demand (COD) in the wastewater rose. The heterotrophic denitrifying bacteria in the system used the reducing sugar in the waste molasses as a carbon source to proliferate. Although the heterotrophic denitrification process can contribute to the removal of total nitrogen to some extent (by reducing some nitrates), the excessive proliferation of heterotrophic denitrifying bacteria weakened the absolute dominance of autotrophic anaerobic ammonia oxidizing bacteria in the system, which caused some interference with the maintenance of AnAOB purity and the long-term autotrophic denitrification environment.

[0040] Example 6

[0041] This example is used to verify the reaction between the maximum concentration (5%) of waste molasses and Fe. 2+ The synergistic enhancement effect was achieved by referring to Example 1, except that the parallel experiments of ferrous sulfate heptahydrate were replaced with the following experiments: Four parallel experiments were set up, with three parallel samples in each group. The operation period was 64 days. The specific grouping is as follows: Blank control group (CK): No waste molasses and Fe were added. 2+ ; Separate waste molasses group (F5): Add pretreated waste molasses accounting for 5% of the total volume of the final reaction system; Fe alone 2+ Group (Fe5): Fe was added to a final concentration of 5 mg / L. 2+ ; Composite group (FF5): Simultaneously adding 5% of the total volume of pretreated waste molasses and 5 mg / L Fe to the final reaction system. 2+ ; Supernatant was collected every 24 hours, and the concentrations of ammonia nitrogen, nitrite nitrogen, and nitrate nitrogen in the supernatant were tested. The total nitrogen removal rate was calculated. After the 64-day operation cycle, the sludge-water mixture was collected to test the specific activity (SAA) of anaerobic ammonia oxidizing bacteria and to calculate the relative activity (RAA) of anaerobic ammonia oxidizing bacteria.

[0042] like Figure 7As shown, a 5% volume fraction of waste molasses has reached the critical load limit of this synergistic denitrification system. Excessively high concentrations of organic carbon sources lead to the proliferation of heterotrophic denitrifying bacteria and the production of large amounts of sludge. This not only coats the anammox granular sludge but also hinders the diffusion and mass transfer of ammonia nitrogen and nitrite into the Anammox bacteria. Experiments have shown that a waste molasses volume fraction controlled within the range of 1% to 5% can trigger a synergistic enhancement effect, but 5% is the recommended upper limit for maintaining the autotrophic dominance of the Anammox system in the specific embodiments of this application.

Claims

1. A method for using molasses to complex ferrous ions and synergistically strengthen an anaerobic ammonia oxidation denitrification system, characterized in that, The method is specifically as follows: Under anaerobic conditions, ferrous ions and electron shuttle industrial waste molasses are added to the wastewater to be treated containing anaerobic ammonia oxidation activated sludge to carry out an anaerobic ammonia oxidation reaction. During the reaction, the anaerobic environment is maintained, the dissolved oxygen (DO) is controlled between 0.2 and 0.5 mg / L, and the system pH is controlled between 7.0 and 7.

8. The wastewater to be treated contains ammonia nitrogen and nitrite nitrogen.

2. The method of claim 1, wherein, In the method, the concentration of volatile suspended solids (MLVSS) in the wastewater to be treated is 2000–3000 mg / L; and / or The ammonia nitrogen concentration in the wastewater to be treated is 50–200 mg / L, and the nitrite nitrogen concentration is 60–260 mg / L.

3. The method of claim 1, wherein, In the method, the temperature of the anaerobic ammonia oxidation reaction is controlled at 35±1℃.

4. The method of claim 1, wherein, In the method described, the final concentration of ferrous ions in the system is controlled to be 1–10 mg / L.

5. The method of claim 1, wherein, The ferrous ions are added in the form of hydrated ferrous sulfate.

6. The method of claim 1, wherein, The industrial waste molasses is put into use after pretreatment. The pretreatment steps are as follows: dilute the industrial waste molasses with warm water at 50-60°C, stir evenly, and adjust the pH to 4.0-5.0 using inorganic acid; then let it settle for 12-24 hours to remove insoluble suspended solids and collect the clear liquid; sterilize the clear liquid with high-pressure steam, cool it and store it at 4°C in the dark.

7. The method of claim 6, wherein, In the method, the volume concentration of pretreated waste molasses in the control system is 1% to 5%.

8. The method of claim 1, wherein, The method employs either a sequential batch processing (SBR) or a continuous stream operation mode.

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